Zulkifli, also known as Marwan, was the main target of the chaotic January 25 anti-terror operation on a remote town.
A top militant in the Southeast Asian terror group Jemaah Islamiyah, he is a key suspect in the 2002 Bali nightclub bombings which killed 202 people as well as two deadly Philippine bombings.
The Federal Bureau of Investigation (FBI) tested a biological sample from a body identified by Philippine police as Zulkifli, David Bowdich, assistant director in charge of the FBI's Los Angeles field office, said in a statement sent to AFP Thursday.
"Although the results of the DNA examinations do not provide absolute identification, the results do support that the biological sample provided by Philippine authorities came from Marwan," he said, adding further tests will be conducted.
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Asked about the US report, Philippine police chief Leonardo Espina said the government will make a statement on the issue shortly.
"Hopefully it will be today," he told a news conference on Thursday.
Police were attacked by at least two Muslim rebel groups during the raid on Zulkifli's hideout on remote and swampy farmland in the southern island of Mindanao.
Espina said most of his men were ambushed and then desecrated by the rebels, who included members of the Moro Islamic Liberation Front, which signed a peace agreement with Manila last year.
The bloodshed has put the peace deal, which commits Manila to passing a law giving the Muslim minority self-rule in a few southern provinces of the mainly Catholic Asian nation, in doubt.